I have these same panniers. Bought them from the same website. They work great for me after one year of regular loaded use on both front and rear racks. None of the hardware has come loose or bent or broken and I've given it a workout, sometimes sandwiching them between my front rack top and a bungied u-lock. The are closed with zippers, but have two sets of long compression laces across each so they can take up minimal space (almost flat) when empty and you can lace them to keep your load tight to your rack/frame. They aren't specifically waterproof, but when I have used them in light rain, the content stayed dry.

The only downside I can think of is that the zippers ends can be noisy if you don't secure them or tuck them into the bag. And if you spill blueberries in one, it will keep smelling like blueberries. The laces seem like they could easily catch in the spokes (especially on my front rack), but that's never actually been a problem.

I'm surprised I haven't seen more of these around. I mean, Ortliebs are awesome, but probably overkill for many users who would do fine with a pair of Bushwackers.